With the arrival of the era of global boiling, accurately analyzing the impact of extreme temperatures on China’s economic and financial system has become an essential issue. To address the challenges in temperature measurement posed by China’s vast diversity, this paper employs a distance minimization approach to match Chinese publicly listed companies with 0.5°×0.5° latitude and longitude grid nodes. This methodology facilitates the precise calculation of the number of days each company is exposed to extreme temperatures, leading to the establishment of first, second, and third-tier extreme heat indicators.On this basis, spatial heterogeneity characteristics of China’s natural environment and economic society, such as geographical zoning and industry classification, are considered to clarify the mechanism of the impact of high temperature exposure on corporate default risk. Simultaneously, this paper investigates the long-term effects of extreme heat on both revenue and expenses.Furthermore, an in-depth investigation into the macroeconomic fluctuations induced by extreme high temperatures is conducted, providing a comprehensive quantitative analysis of the impact of varying heat levels on key macroeconomic variables, such as GDP and inflation rates, in major cities across China.Finally, several policy recommendations are suggested to effectively address global climate change and establish a long-term mechanism for mitigating climate financial risks, thereby offering guidance for promoting sustainable economic and social development.